Because I tripped over a bug in Firefox that caused another problem not
germane here, I upgraded my FC6 box to the latest 3.0 beta (3.0apre) for
a few days. Actually I ran both versions.
I didn't follow any of the advice given so far. IIRC I untarred it in a
new directory, changed the /usr/bin/firefox link to point to the
executable, installed the plugins I wanted, and it found my bookmarks. I
think I did something to accomodate the profile. Sorry I can't remember
exactly, but I followed the beta-tester instructions that let you run
multiple versions. Definitely backup your bookmarks, and all the
.mozilla directory before you do this. Maybe even better to try it on a
dummy user. Like me, you'll say? ;>) Seriously it wasn't bad at all,
Mozilla is doing pretty well at keeping all their files in one or two
places.
Hoping this is more helpful than confusing...
John